Apparatus for quenching steel plate



Dec. 15, 1970 w. H. LENZ APPARATUS FOR QUENCHING STEEL PLATE 4.Sheets-Sheet 1 Fi led March 29, 1965 INVENTOR. WALTER H. LENZ ATTORNEYSDec. 15, 1970 w. H. LENZ 3,546 9 I APPARATUS FOR QUENCHING STEEL PLATEFiled March 29, 1965 4 Sheets-Sheet 2 INVENTOR. WALTER H. LENZ ATTORNEYSDec. 15, 1970 w. H. LENZ APPARATUS FOR QUENCHING STEEL PLATE 4Sheets-Sheet 5 Filed March 29, 1965 EOPFOm N UZON QOF N mZON v UZON@tqwmm QO-r wZON EOPFOm QOP EOPPOQ mZON m UZON QOP . m mZON I NVENTOR.WALTER H. LENZ ATTORNEYS Dec. 15, 1970 w. H. LENZ 3,546,911

APPARATUS FOR QUENCHING STEEL PLATE Filed March'29. 1965 4 $heets+Sheet4.

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WALTER H. LENZ I ATTORNEYS United States Patent 3,546,911 APPARATUS FORQUENCHING STEEL PLATE Walter H. Lenz, Washington, Ill., assignor toCaterpillar Tractor Co., Peoria, Ill., a corporation of California FiledMar. 29, 1965, Ser. No. 443,558 Int. Cl. B21b 27/10; C21d 1/62 US. Cl.72201 2 Claims ABSTRACT OF THE DISCLOSURE Apparatus for quenching steelplate by holding it between sets of rollers which retain it in flatcondition and also driving the rollers to reciprocate the plate whileapplying quench in such large quantities as to maintain the plateentirely immersed in quench.

Success in increasing the horsepower and performance of engines used inall types of automotive equipment has dictated corresponding increasesin strength and durability of its mechanisms and structural members.Where it is economically justifiable, it is the practice to employ steelhaving various alloying ingredients which provide such increases instrength and durability. Attempts in conditioning low-carbon steel platehaving the desired properties have met with limited success due tononuniform hardness characteristics and plate warpage.

Treatment of low-carbon steel plate to produce desired physicalproperties of toughness and resistance to deflection is presentlyaccomplished by use of a platen press employing hold down fingers whichengage the plate while it is being quenched. The plate produced by thismethod of treatment fails to give the desired physical properties mainlybecause of non-uniform and rather slow quenching and because the holddown fingers conduct heat from the plate before and at a different ratethan the quenching fluid. These fingers also tend to baflle the waterduring the quench.

Experiments conducted with low-carbon steel plate have shown that therate and uniformity of quench are of paramount importance to achievedesired qualities of toughness and flatness. In achieving this result,the method of the present invention locates the plate desired to beprocessed between sets of ribbed rolls, functioning to straighten thehot-plate prior to its being quenched, and then sprays water or othersuitable quenching fluid to the opposite sides of the plate so held bythe ribbed rolls. By providing ribbed rolls the area of plate contact isminimal thus substantially reducing the quantity of heat transferredfrom the plate, and the quenching fluid is supplied in suflicientquantities to actually flood the plate.

It was found that 70 to 150 gallons per minute per square foot ofsurface on each side of the plate resulted in a rate of quenching whichprevented the plate from buckling or warping.

Although the particular apparatus disclosed in this invention is merelyrepresentative of a preferred form of construction, the basic functionsthereof were dictated by the salient method steps. The apparatus is sodesigned that a plate approximately 12 feet long and 48 inches wide mayhave a selected portion thereof quenched. This is accomplished byproviding selectively operable spray bars, overlying the upper and lowersurface of the plate, and suitable controls to admit water or othersuitable quenching fluid to desired ones of such spray bars. In thismanner, it is possible to quench a longitudinal strip of the plate or aportion extending the entire width and a portion of its length. Forexample, it is possible to quench a strip 18 inches wide and 12 feetlong or a strip 48 inches wide and 6 feet long.

In contrast to present quenching practices, the plate 3,546,911 PatentedDec. 15, 1970 quenched by the present invention is waltzed orreciprocated between selected limits during the quenching operation.Such reciprocation insures uniform quenching and assists in maintainingthe plate flat.

Accordingly, it is an object of this invention to quench steel plate bya method which maintains its flatness.

Another object of this invention is to prevent distortion of flat steelplates by uniformly and simultaneously distributing quenching fluid tothe surfaces of such plate.

Another and more particular object of this invention is to quench steelplates in order to maintain their flatness by a method whereby the plateis reciprocated while it is being subjected to large quantities ofsprayed quenching fluid.

A further object of this invention is to provide an apparatus forcarrying out the method of this invention.

Another object of this invention is to reciprocate and restrain a flatplate against distortion during the quenching operation.

Still another object of this invention is to provide a new and improvedplate quenching apparatus which is automatic in operation.

These and other objects and advantages of the invention will, however,hereinafter more fully appear in the course of the ensuing description.

Reference will now be made to the drawings for a more particularizeddisclosure of the invention, wherein:

FIG. 1 is a perspective, with parts broken away, showing a preferredform of the apparatus for carrying out the method;

FIG. 2 is an enlarged transverse section taken substantially along theline IIII of FIG. 1;

FIG. 3 is a diagrammatic perspective of a representative number of spraybars, the quenching fluid distribution system, and a suitable plateshown in phantom outline and which is divided into four quenching zones;

FIG. 4 is an enlarged side view of FIG. 1 showing a plate locatedbetween the roller frame and the spray pattern of the spray bars; and

FIG. 5 is a longitudinal section of a spray bar taken substantiallyalong the line VV of FIG. 4.

Now, referring to FIG. 1, it will be seen that the quenching apparatusconstructed according to this invention includes a quenching unit 10being in the form of an elongate, generally rectangular, housing andincluding a lower stationary roller frame 12 rotatably supporting aplurality of longitudinally spaced transversely extending rollers 14which are provided with regularly axially spaced ribs 16. A verticallyreciprocable roller frame 18, including similarly formed rollers 20rotatably mounted thereon is positioned so that rollers 20 are invertical alignment with the rollers 14. Ribs 22 are also formed on therollers 20 and are located to be co-planar with the ribs 16.

The longitudinal spacing of the rollers 14 and the rollers 20 aresufficient to provide the inclusion of spray bars 24 and 26 beingassociated, respectively, with the frame 12 and the frame 18. Each ofthe rollers 14 has reduced diameter portions extending through bearings28 which are suitably mounted on the side rails of the frame 12. Thesereduced diameter portions have sprockets 30 rigidly mounted thereonwhich are in meshing engagement with suitable chains 32 being driven bya drive mechanism 34.

The drive mechanism 34 is associated with a control circuit which isresponsive to the position of a plate located in the quenching unit tocause reversible rotation of the rollers 14. A quenching fluiddistribution system generally indicated by the numeral 36 is arranged toprovide flow of quenching fluid to selected ones of the upper and lowerspray bars so that if it is desired just a portion of the plate may bequenched. Of course,

this quenching fluid distribution system is also operable to supplyquenching fluid to all of the upper and lower spray bars at the sametime.

As shown in FIG. 1, a hot-plate, indicated by the letter P and supportedon a suitable transport table 38, is fed between the forward-most lowerand upper sets of rolls whereupon the plate is transported inwardly intothe quenching unit for processing.

Referring now to FIG. 2 which shows a vertical transverse section of thequenching unit 10, it will be seen that the upper rollers 20 have theirribs 22 closely adjacent the ribs 16 of the lower rolls 14. When a plateis inserted into the quenching unit, its thickness is suf ficient tocause upward movement of the roller frame 18 and in this manner pressureis applied to the opposite surfaces of the plate while it is in thequenching unit. To allow such vertical movement of the upper frame 18,there are provided vertical guide rods 40 which are secured to thestationary frame 12 and are received in suitable bores 42 formed in theupper frame 18. Accordingly, when the plate is fed into the quenchingunit, the upper frame 18 moves upwardly and its weight is transferred tothe plate through the ribs 22 and in this manner the power is impartedto the lower rollers 14 by the drive mechanism 34 causing rotation ofthe upper rollers which are in frictional engagement with the plate. Byproviding ribbed rolls, spaced longitudinally of the plate, a minimumarea of contact results since each of the ribs in contact with the plateestablish line contact which assists in reducing transfer of heat fromthe plate to the rolls and consequently prevents premature partialquenching.

After the plate has reached a pre-determined position in the quenchingunit 10, an electrical circuit is energized conditioning the drivemechanism 34 to alternate the di- I rection of rotation of the rollers14 in order to reciprocate the plate during the quenching operation. Inthe form illustrated in FIG. 1, the drive mechanism 34 may include amotor 46 for drawing the plate P into the quenching unit and forejecting the plate P from the unit at relatively high speed. The motor46 is connected to a gear reduction unit 48 on whose output shaft ismounted an electric clutch 50. In this arrangement, the sprocket chain32 is trained about a drive sprocket 52 which is connected to a shaftextending from the electric clutch 50 to a second electric clutch 54which is in turn connected to the output shaft of a torque motor 56. Themotor 56 is controlled to drive the chain 32 first in one direction fora fixed period of time and then to drive the chain 32 in the oppositedirection for a fixed period of time so as to move the plate P back andforth between the orifices. The direction of rotation of motor 56 andthe duration of rotation in either direction can be controlled manuallyor automatically by limit switches and timers. The motor 56 preferablyoperates at a lower speed than the motor 46.

When a plate P to be heat-treated is placed on the transport table 38 inthe position shown in FIG. 1, the operator closes the switch energizingthe motor 46 and the clutch 50 in a direction causing the lower rolls 14to draw the plate into the quenching unit. As the plate progressesinwardly a sufficient distance, it encounters a limit switch which opensa circuit de-energizing the motor 46 and the clutch 50 While at the sametime the torque motor 56 and the clutch 54 are energized. Atsubstantially the same time as the motor 56 and the clutch 54 areenergized, quench valves 58 are opened permitting a quenching fluid tobe distributed to the upper and lower sets of spray bars. As notedabove, the control circuit may include timers (not shown) ofconventional design which operate to maintain the motor 56 and theclutch 54 energized for a predetermined period of time during which theplate is waltzed or reciprocated between selected limits in thequenching unit by periodically changing the direction of rotation ofmotor 56. Upon elapse of this period of time, the timer deenergizes themotor 56 and the clutch 54, closes the quench valves 58, and energizesthe motor 46 and the clutch which now causes rotation of the lower rolls14 in a direction which ejects the plate from the quenching unit ontothe transfer table 38. In an alternate form of drive mechanism 34 (notshown) a single two-speed motor can be arranged to produce the samefunction as provided by the two motors 46 and 56.

Thus, it is seen that the quenching apparatus according to thisinvention is automatically operable to insure uniform and rapidquenching of a plate and at the same time prevents warping or distortionof the plate while it is being quenched.

Referring now to FIG. 3 which shows the arrangement of the quenchingfluid distribution system and selected ones of the upper and lower spraybars, it will be seen that the plate illustrated in phantom outlinelocated between the upper and lower spray bars 26 and 24, respectively,is divided into four areas designated as Zones 1, 2, 3, and 4. Inaccordance with one of the basic features of this invention, thequenching fluid distribution system 36 can be conditioned for operationwhereby a selected portion of each plate may be more severely quenchedthan the remaining portion. For example, the spray bars may be operatedto apply much greater quantities of quenching fluid to Zones 1 and 3 andthereby quench a longitudinal strip of the plate which will have a valueof hardness greater than the longitudinal strip defined by Zones 2 and4; or the quenching fluid may be distributed so that Zones 1 and 2 or 3and 4 may be quenched more severly to thereby produce selected values ofhardness. Not only are the quench valves 58 programmed to open or remainclosed in the event it is desired to produce selective quenching, butthe spray bars themselves are constructed in a manner which assists inproducing such selective quenching.

Referring to FIG. 5 which shows a longitudinal section of a typicalspray bar, which for matter of convenience has been chosen as one of theupper spray bars 26, it will be seen that it includes a transverse discshaped wall to which is attached oppositely extending longitudinallyaligned tubes 62 being provided with a series of orifices 64 throughwhich issue the quenching fluid. Quenching fluid is admitted to eitherof the tubes 62 by a separate manifold which is part of the quenchingfluid distribution system. In this way, it is readily apparent that whenthe appropriate quenching valve 58 is open communicating quenching fluidto one of the tubes 62, no fluid will flow through the other tube if thecorresponding quenching valve is closed.

Referring again to FIG. 3, it will be seen that by opening the quenchingvalves 58 supplying quenching fluid to the spray bars overlying andunderlying zones 1 and 3 while the quenching valves supplying the spraybars overlying and underlying Zones 2 and 4 are closed, selectivequenching of the plate occurs.

Referring to FIG. 4 which shows an enlarged longitudinal section of aportion of the quenching unit with the plate located between the lowerand upper rolls, it will be seen that sufficient distance is providedbetween the sets of rolls to accommodate two spray bars. Each of thespray bars is provided with three rows of orifices 64 to produce a spraypattern which substantially evenly distributes equal amounts ofquenching fluid per unit of area of the plate. Upon initiation of thequenching opera tion, quenching fluid is distributed in streams producedby each orifice 64 but shortly thereafter the orifices become submergedsince the quenching unit is constructed to actually flood the plate.Flooding of the area above and below the plate and submerging of thespray bar orifices is accomplished by the spacing of the spray bars androllers associated with the roller frames 12 and 18 (FIG. 2). During thequenching operation, the area adjacent the upper and lower platesurfaces fills with the quenching fluid submerging the plate and theorifices 64 of spray bars 24 and 26. In order to prevent rapid escape ofquenching fiuid along the lateral sides of the quenching unit 10, bafileplates 66, supported by the roller frame 18, and overlapping bafileplates 68 are supported on the stationary frame 12.

Accordingly, during the quenching operation which occurs while the plateis being waltzed or reciprocated between the desired selected limits.the quenching fluid issuing through the orifices 64 of the upper andlower spray bars is of sufficient quantity to submerge all orifices 64.It has been found that a value of pressure of 50 pounds per square inchat each of the orifices 64 produces a high degree of turbulence orwiping of the quenching fluid which in turn assures a substantiallyuniform and rapid rate of heat transfer from the plate being treated.

Thus, according to this invention, it will be seen that a quenchingprocedure is obtained which holds a plate to assume a planarconfiguration and while being so held, the plate is waltzed orreciprocated and quenched for a pre-determined period of time.

I claim:

1. Apparatus for quenching steel plates comprising spaced supportrollers arranged to support the plate to be quenched at intervalsthroughout the plates entire length and width, pressure rollers disposedabove the plate and registering with the support rollers to hold theplate flat, a plurality of integral circumferential ribs spaced axiallyalong the length of said support rollers and upper rollers and whereinthe outer circumferential surfaces of said ribs contact said plate,means to rotate said support rollers in opposite directions duringsequential periods of time to cause the plate to reciprocate while beingconfined between the support and pressure rollers, and perforated tubesfor liquid quench arranged between some of the pressure rollers to sprayquench downwardly against the plate as it reciprocates, and similartubes between some of the support rollers simultaneously to spray quenchupwardly against the plate, and the spacing between the said support andpressure rollers and the quench tubes associated therewith being limitedsuch as to retard the flow of quenching fluid to the extent that theentire plate is immersed during the quenching operation.

2. Apparatus for quenching steel plates comprising spaced supportrollers arranged to support the plate to be quenched at intervalsthroughout the plates entire length and width, upper rollers disposedabove the plate and registering with the support rollers to maintain theplate fiat, a plurality of integral circumferential ribs spaced axiallyalong the length of said support rollers and upper rollers and whereinthe outer circumferential surfaces of said ribs contact said plate,means to rotate at least said support rollers in opposite directionsduring sequential periods of time to cause the plate to reciprocatewhile being confined between the support and upper rollers, andperforated tubes for liquid quench arranged between some of the upperrollers to spray quench downwardly against the plate as it reciprocates,and similar tubes between some of the support rollers simultaneously tospray quench upwardly against the plate.

References Cited UNITED STATES PATENTS CHARLES N. LOVELL, PrimaryExaminer US. Cl. X.R.

